Some companies operate systems that perform communication using high-level data link control (HDLC) or a protocol which is a unique protocol other than the transmission control protocol/internet protocol (TCP/IP). In such systems, when communication is performed via a wide area network (WAN), a WAN line using a protocol other than the TCP/IP is used. Hereinafter, the WAN line using a protocol, such as the HDLC or a unique protocol, other than TCP/IP is also referred to as a “legacy WAN line.”
In the past, when a computer that performs communication using the TCP/IP performed communication using a legacy WAN line, a network card configured to perform communication using the legacy WAN line was mounted on the computer in order to perform communication. Hereinafter, the network card configured to perform communication using a legacy WAN line is also referred to as a “line card.” In such communication, data obtained by adding a WAN protocol header defined in accordance with a protocol used for communication using the legacy WAN line to user data is transmitted and received via a line card.
In recent years, an operation form, such as a cloud service, has been spread in which a user accesses an external system via a WAN and receives a service using resources of a system of an access destination. In such a service, various virtualized resources such as virtual machines are provided in many cases.
As a technology using a virtual machine, there is a conventional technology in which when there are a plurality of virtual machines with the same IP address and different MAC addresses, one representative virtual machine transmits and receives data to and from the outside to transmit data between other virtual machines. Further, as a technology for connecting a LAN to a WAN, there is a conventional technology for encapsulating data with a PPP communication frame and causing a terminal in a household local area network (LAN) to communicate with a terminal connected to a public network. Furthermore, as a technology for a virtualization system, there is a conventional technology in which when there are a plurality of virtualization systems, an optimum amount of computer resource is provided to users.
Patent Literature 1: Japanese Laid-open Patent Publication No. 2007-110240
Patent Literature 2: Japanese Laid-open Patent Publication No. 2004-222059
Patent Literature 3: Japanese Laid-open Patent Publication No. 2010-250778
When a system using a legacy WAN line uses a service such as a cloud service, the following problems may occur. A line card is hardware that is uniquely made to perform communication using a legacy WAN line. For example, the line card stores operation information at the time of communication in an internal memory or a register in many cases. When such a line card is used, it is difficult for a virtual machine other than a virtual machine that performs communication using the line card to use the information stored in the line card. For this reason, even when attempting to switch a virtual machine by performing migration, a virtual machine of a migration destination is not able to use the information in the line card, and thus is not able to perform communication. That is, when the line card is used, the migration function in the virtualization technology is not able to be used. Thus, when the line card is used, it is not possible to cope with a general virtualization technology, and therefore it is difficult to embed the line card in the general virtualization technology. For this reason, it is difficult for a system using a legacy WAN line to receive a service from a virtualization system.
Even in the conventional technology for causing one representative virtual machine to transmit and receive data to and from the outside, it is difficult to embed the line card in a virtualization technology and it is difficult to associate a system using a legacy WAN line with a virtualization system. Further, in the conventional technology for causing a terminal in a household LAN to communicate with a terminal connected to a public network, it is assumed that both the terminals perform TCP/IP communication and it is difficult to associate a system using a legacy WAN line with a virtualization system. Furthermore, in the conventional technology for providing users with an optimum amount of computer resource from a plurality of virtualization systems, it is also difficult to embed a line card in a virtualization technology and it is difficult to associate a system using a legacy WAN line with a virtualization system.